# Teaching experiences help students “think like an engineer” | Imperial News

Dr. Peter Johnson talks about students returning to in-person teaching and conducting experiments.

“In early February 2022, second-year mechanical engineering students performed experiments to study transient heat transfer. They used cups of hot and cold water to characterize the response of a temperature probe. Each student had their own kit, but now that the lockdown is over, they were able to collaborate, which not only led to more learning, but also a great atmosphere in the room that we all enjoyed.

The probe studied by the students takes time to react to changes in temperature. Students had to characterize this response in the context of two applications in the combined heat and power (CHP) plant, to help determine if the probe could be used – i.e. does it respond sufficiently rapidly ? This real app helps students think like an engineer and find practical solutions.

This was an “inquiry” based session that encouraged students to find their own path and make their own decisions. The survey approach can be uncomfortable and difficult, but it is closer to the experience of a professional engineer and helps foster the independence we want our graduates to develop.

The probe is complex because it contains different parts made of different materials and whose geometry is not simple. It is difficult to fully model this probe in detail, so the students tried to use a “lumped capacitance” model that combines all of the probe’s thermal characteristics into a single parameter. This approach provides a relatively simple mathematical model that is useful to engineers.

Students derived their own mathematical model and used their measurements to verify the general modeling approach and to tune the parameters of their model. The more ambitious students also attempted to validate the model with tricky experiments that continuously varied the temperature around the probe.”

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**Nadia Barbou**

Department of Mechanical Engineering